This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cytonemes are long filopodial processes we believe are used in long range signaling of growth factors during development. Cytonemes express growth factor receptors and extend up to 800 um before contacting their target cells in the imaginal disk. We wish to use electron microscopy to study the contact points between cytonemes and target cells in Drosophila larvae.